This disclosure relates to wireless energy transfer, methods, systems and apparati to accomplish such transfer, and applications.
Audio devices such as headphones, personal speakers, headsets, and the like require electrical energy to produce an audio output or provide noise cancellation. The electrical energy for such devices is usually delivered from disposable batteries and/or a wired connection to an energy source such as a stereo, mobile device, or a music player. Existing methods reduce the utility, comfort, and convenience of the audio devices for many applications. Headphones, for example, are worn on the user's head or neck area which often limits the weight and/or size of the devices and may limit the size of the batteries that may be comfortably tolerated by the user. Smaller batteries result in shorter use windows or frequent replacement and/or recharging of the batteries. Cables that tether the audio devices to power sources may limit the mobility of the audio devices and may pose a tangling hazard and limit the reliability of the audio devices. These limitations are magnified when considering venues and or environments for which hundreds or thousands of person-worn devices are worn or used. Theaters, airplanes, work environments, and the like, that may rely on person audio devices may need to accommodate battery supplies and chargers for the devices and/or mitigate the consequences of reduced mobility and reliability due to cables. Methods that reduce or eliminate the need for batteries or cabled sources for energy would increase the utility and convenience of the devices in many applications.
In addition to the audio devices described above, wireless energy transfer may be used to recharge the batteries of small audio devices without having to remove the batteries. BlueTooth® headsets may benefit from this technology because the connector used to recharge the batteries using a wired solution may be eliminated, making the headsets more compact and allowing for new designs that are unconstrained by the presence of the electrical connector. In addition, hearing aids may be recharged by simply placing them on a charging mat or in a charging bowl or enclosure or region. Wireless recharging may eliminate the need for an accessible battery compartment in the hearing aid, which will make it easier for uses users to keep the devices charged and may also make it easier to clean and maintain the devices.